1. Technical Field of the Invention
The present invention relates to an improved method of making a self-aligned conductor in semiconductor device, that reduces the contact area. More particularly, this invention relates to a method of making a self-aligned contact in a semiconductor device, including filling a contact hole with thermal oxide spacer.
2. Description of the Prior Art
Generally, in a semiconductor device equipped with multi-layer conductive lines, the contact which connects the conductive lines vertically should be insulated from other layers. In a prior art, a method of making a contact of a semiconductor device having 3-layer conductive line was as follows:
On a semiconductor substrate, there was formed a series of the first conductive line, the first dielectric layer, a series of the second conductive line, and the second dielectric layer successively. By removing an appropriate part of the second dielectric layer and second conductive line, the contact hole exposing the first conductive line is formed. Also, the third conductive line, which fills up the contact hole, is connected to the first conductive line. Between the third conductive line, filling up the contact hole and the second conductive line, the second dielectric layer is inserted to maintain a certain distance.
To maintain regular intervals between the third conductive line and second conductive line nearby the contact hole, the etching mask of the third conductive line and the etching mask of contact hall should be in accordance with the standard design rule, and the following factors should be considered;
1) Misalignment tolerance in forming pattern, lens distortion, and critical dimension variation.
2) Registration between mask and mask.
3) Thickness of dielectric layer within the contact hole. The aforementioned contact of the prior art in manufacturing contact has the problems of enlarging the contact area owing to the above-said factors.